Transmission



Aprifi 7, 1936.

W. A. GARRATT TRANSMISS I ON 5 Sheets-Sheet 1 Original Filed Sept. 9,1932 INVENTOR.

ATTORNEY- April 9 6- w. A. GARRATT mswzs TRANSMISSION Original FiledSept. 9, 1932 3 Sheets-Sheet 2 INVENTOR. BY Wk WM ATTORNEY.

pin-ill 1936. w. A. GARR TRANSMISSION Original Filed Sept. 9, 1932 3Sheets-Sheet 3 ATTORNEY- Patented Apr. 7, 1936 UNITED STATES PATENTOFFICE 11 Claims.

My invention relates to transmissions, and is particularly directed toimprovements in adjustable crank pin mechanism.

The objects of this invention are to provide first a range of variationor adjustment with an infinite number of crank pin positions from zeroeccentricity up to the maximum throw provided in the design of themachine; second, to allow adjustment while the mechanism is in motion;and third, to provide for automatically locking the crank pin or othermember in any selected eccentric relationship to the drive shaft axiswithout strain on the adjusting parts.

The present application is divisional of my copending application SerialNumber 632,407, filed September 9, 1932, for Variable speed powertransmission.

.Other objects and further advantages will be more fully apparent from adescription of the accompanying drawings, in which:

Figure 1 is a longitudinal vertical cross sectional view of the deviceof this invention.

Figure 2 is an exploded View drawn to a larger scale than Figure l, andshowing the essential parts of the device.

Figure 3 is a face view of one of the driver discs.

Figure 4 is a side View thereof.

Figure 5 is a face view of one of the suspension bodies.

Figure 6 is a side View thereof.

Figure 7 is a sectional View taken on line 1-1, Fig. 1.

Figure 8 is a sectional View taken on line 88, Fig. 1.

Motion may be transmitted through this device from either end to theother, but it will be assumed for the purpose of description of theparts and their relationship that 5 is a drive shaft in the form of asleeve connected by any suitable coupling as 6 to the drive shaft I ofany source of motive power (not shown). The drive shaft or sleeve 5 isjournalled in ball bearings 8 in a hub 9 of a transmission frame orhousing I which may have a base as at I I. The Wall of the sleeveincludes a spiral slot I2. Rotatably fitting in the sleeve 5 is a shaftI3 extending from a point beyond the outer end of the spiral slot I2into the interior of the transmission housing. The shaft I3 has alongitudinal groove or keyway I4 formed therein. Around the sleeve 5 isa circumferentially grooved collar I5 which is longitudinally slidableon the sleeve 5. In the groove of the collar I5 is fitted the forked endI6 of a control lever I! which is pivoted on a stud I8 which is fixed inan arm IQ of the housing ID. This arm may be attached to the floor orwall or any stationary object as may be convenient.

In the collar I5 is fixed a pin 20 extending from the surface of thegroove in the collar inwardly "throughthe spiral groove I2 of the sleeve5 and Divided and this application January '7, 1935, Serial No. 692

into the straight groove I4 of the shaft I3. This pin does not extendinto the control lever forked end. It should of course be preferably ofa diameter snugly slidably fitting the width of the groove and slot soas to prevent back lash. From this description it follows that thecollar I5 will rotate with the sleeve 5 and as it is movedlongitudinally by shifting the control lever I1 the angular relationshipof sleeve 5 and shaft I3 will be changed and that this shift may beaccomplished while the sleeve 5, which is the drive member, is rotating.

Obviously the same function would be performed if the slot I2 werestraight and the groove I4 were spiral or if both groove and slot werespiral but were relatively angular to each other. Also, it is understoodthat this means of changing the angular relationship of two membersrotating on the same axis is well known in the art and that other meansfor performing this function such as differential gearing are also wellknown.

At the inward end of the sleeve 5 as an integral part thereof is ahollow cylinder or bell shaped casing 2|. At the inward end of shaft I3a disc shaped member 22 is fixed thereto within the casing 2I andconcentric to it. The disc mem ber 22 includes a circular recess 23which is eccentric to the axis of the shaft I3 and which contains,fitted loosely, the hub 24 of a gear 25 carrying a crank pin 26. Thelast three members 24, 25 and 26, are fixed in relationship to oneanother and are preferably in one piece as shown and may be hereinafterreferred to as the crank pin ele ment 2?. The crank pin 26 is eccentricto the hub 25 by the same amount that the recess 23 is eccentric to theaxis of the shaft I3. The spur gear 25 is concentric with the hub 24 andits teeth engage the teeth of an internal gear member 28 which isfastened to the open face of the bell shaped casing 2I and is concentricto it. Other means than the gears could be used for constraining themovement of the hubin relation to the casing 2|.

It is seen therefore that as the disc member 22 rotates with the shaftI3 in relation to the bell shaped casing 2I it will rotate the crank pinelement 2'! about the same axis and, the gear teeth of spur gear 25being constantly in mesh with the internal gear teeth of gear 28, thecrank pin element 21 will also rotate on its own axis. The two movementswill cause crank pin 26 to move through a range between a positionconcentric to the axis of the drive shaft 5 which is the same as theaxis of shaft I3 to a position eccentric to that axis by the amount ofthe sum of the eccentricity of the recess in relation-to the drive shaftaxis and the eccentricity of the crank pin 26 in relation to the crankpin element 21.

It is further evident that if the two eccentricities last referred toare made of unequal measurements the crank pin 26 cannot be brought to aposition concentric to the drive shaft axis. In such case, when thecrank pin mechanism is driving a transmission of the type hereinafterdescribed, the output speed of the transmission cannot be reduced tozero and this limitation may be had.

A plate 29 is fastened to the outer face of the internal gear 28 and isprovided with a perforation 30 through which the crank pin-2G'extends.This plate maintains the various parts within the casing 2! so thattheir axes remain parallel. The perforation 30 is of such size and shapeas to limit the position of the crank pin 26 to the range of movementfrom the position of concentricity with the drive shaft axis to theposition of maximum eccentricity, and it is possible by altering theperforation to impose any desired limits within this range.

The spiral perforation |2 in thesleeve 5 and the straight groove I4 inthe shaft 13 are of a length and relative pitch which will providesufficient relative angular change between the sleeve 5 with its bellshaped casing 2| and the shaft l3 with its disc member 22 as will causethe crank pin 26 to move through its full range. By shortening thelength of the spiral perforation or of the straight groove, it is alsopossible to limit the range of eccentricity of the crank pin 25 relativeto the drive shaft axis.

Up. to this point in the description, the driving connection between thedisc member 22 and the crank pin element 21 has been considered asoccurring through the contact or fit of the hub 24 in the recess 23.However, it is preferable to provide a clutch mechanism between the discmember 22 and the crank pin element, and in this case the recess is onlyprovided for purposes of clearance for the proper relationship betweenthe clutchmeans, the disc member 22 and the crank pin element.

In the disc member 22 fixed to. the end of the control shaft |3 areformed two slots 3|, 32, through the wall of the recess 23 for receivingrollers 33 and 34, whose axes are parallel to the drive shaft axis. Thesides of these slots are. planes radial to the drive shaft axis and theslots are very slightly wider than the diameter of the rollers. Theseslots are placed on each side of the thickest portion ofthe wall of therecess 23.

Since the recess 23 is eccentric to the face of the disc member 22, thesides of the slots are of unequal length. The average of the length ofthe walls of the slots is slightly less than the diameter of therollers.

In another slot 35 in the thinnest portion of the wall of the recess 23is placed a ball 36 proportioned to its slot as are the rollers 33 and34 to theirs. Also it is evident that the spur gear 25 concentric to thehub 24 and fixed to it, meshes with the internal gear 28 fixed andconcentric to the casing 2| at a point adjacent to the ball 36. theteeth of the two gears are formed so that they bottom without bindingand the pitch line of the gears is properly related to the shaft axis,then the ball 36 may be omited. Plungers 31 and 38 actuated by spring 39urge the rollers 33 and 34 away from each other.

It is now evident that when a load is imposedonthe crank pin 25 opposedto the driving rotation of the drive shaft 5, the hub 24 is constrainedby the gear teeth to press the roller which it tends ,to approachagainst the inner wall of the casing 2| so that driving connectionbetween the drive a t. n he qre ie i tab i hed, ae arins pressingagainst the roller aiding in this function. No practical working loadimposed upon the crank pin 2| can cause the throw of the crank pin tochange and at the same time there is no strain imposed upon the discmember 22 or its control lever I1, and therefore shaft l3 with its discmember 22 is free to rotate with the drive shaft.

If now the control lever be shifted and the disc 22;.caused to rotaterelative to the drive shaft 5 then the thrust of projection 43 againstroller 33 or of projection 4| against roller 34, Whichever isappropriate according to the direction of relative rotation of theadjusting shaft, will unlock the roller from fixed connection betweencasing 2| and hub 24 and as the rollers are moved around the hub, thecrank pin element 21 will rotate on its own axis, being constrained bythe gear teeth, and the throw of the crank pin will be changed. Fromthis explanation it is evident that the cylindrical shape of the rolleris not essential to the operation of the device. Blocks of substantiallythe same shape as the slots in which the rollers are contained could.

be used.

The remaining parts of the mechanism, show herewith, are not part of theinvention disclosed herein, but they or other parts of similar functionmay be driven by the crank'pin of this in vention. A more detaileddescription of these parts is given in the pending application SerialNo. 632,407, filed September 9, 1932, heretofore mentioned and of whichthis application is di- For this disclosure the description is .3

visional. made brief as follows,

Around the crank pin 23 are disposed throw plates 42, 43, and 44, eachhaving a central hole in which is contained a driver disc 45 including adriver shoe 46 which fits upon the crank pin 26. The driver discs 45 bymeans of clutches 4.? are adapted to act as driving connections betweenthe crank pin 23 and the throw plates 42, 43 and 44. These plates aresuspended from the housing l0 by studs 48, 49 and 58, each of whichstuds supports in fixed rotatable relation to each other a set of threesuspension bodies, one on each stud for each throw plate, disposedeccentrically about the studs. The studs and suspension bodies limit themovement. of the throw r plates 42, 43. and 44 to 'pseudo rotation, thatis, the plates cannot rotate on their own centers but their centersdescribe equal circles about a common axis.

A drum shaped member 5| having an inner and adapted to receive thepseud0rotation of the eccentric plates 42 43, 44, and cause rotation ofthe drum shaped member 5| and the driven shaft 53.

The angular movement of pseudo-rotation of the throw plates 42, 43 and44, is proportional to the throw of the crank pin 23.. The rotation ofthe driven shaft is equal to the pseudo-rotation of the throw plates andthe rotation of' the crank pin 26 is equal to the rotation of the driveshaft 5 so that variation in the throw of the crank pin accomplishes-avariation in the ratio of speed between the drive and driven shafts.

Having described my invention, 1 claim:

1. In combination, a sleeve adapted to be rotated, a disc mountedcoaxially with said sleeve and adapted to rotate therewith and relativethereto, said disc having a cylindrical recess parallel with andeccentric to its axis, a cylindrical hub having a crank pin thereon,said hub mounted for rotation in the cylindrical recess, clutch membersinterposed between said hub and said sleeve for a driving connectionbetween the sleeve and the cylindrical hub, and means for rotating thedisc relative to the sleeve.

2. In combination, a sleeve adapted to be rotated, a disc mountedcoaxial with said sleeve adapted to rotate therewith and having acylindrical recess therein eccentric to its axis, a hub member mountedfreely adjustably in the eccentric recess and having a crank pinprojecting therefrom, and clutch members interposed between the hubmember and the sleeve for locking the sleeve to the hub member as thesleeve is being rotated.

3. In combination, a sleeve adapted to be rotated, a disc mountedcoaxially with and adapted to rotate with said sleeve and relativethereto, said disc including a cylindrical recess parallel with andeccentric to its axis, a hub member rotatively adjustably mounted in theeccentric recess in the disc and having a crank pin thereon, lockingelements interposed between the sleeve and the hub member for thepurpose of preventing movement of the hub member relative to the disc ordisc and sleeve when the sleeve is being driven, and means adapted torotate the hub member within the cylindrical recess upon relativerotation of the sleeve and the disc.

4. In a device of the class described, a drive member, a cooperativemember rotatively mounted within a portion of the drive member, a drivenmember having a cylindrical hub eccentric to the axis thereof, saidcylindrical hub rotatively mounted in the cooperative member eccentricto the axis of the drive member, and clutch means interposed between thedrive member and the cylindrical hub for transmitting driving motionbetween the drive member and the cylindrical hub.

5. In a device of the class described, a drive member, a cooperativemember rotatively mounted within a portion of the drive member, a drivenmember having a cylindrical hub rotatively mounted in the cooperativemember parallel with and eccentric to the axis of the drive member,clutch members in the cooperative member, and yielding means engagingthe clutch members and adapted to hold the clutch members in drivingcontact with the drive member and the cylindrical hub when the drivemember is being rotated.

6. In a device of the class described, a drive member, a coacting memberrotatively mounted within a portion of the drive member, a driven memberhaving a cylindrical hub fitting loosely within the coacting memberparallel with and eccentric to the axis of the drive member, clutchmembers mounted in the coacting member and adapted to be released byrelative rotation of the drive member and the coacting member, yieldingmeans for holding the clutch members in driving contact with the drivemember and the cylindrical hub when the drive member is being rotated,and means fixed to the drive member for rotating the driven member aboutthe axis of the cylindrical hub upon relative rotation of the drivemember and the coacting member.

7. In a device of the class described, a drive member, a coacting memberrotatively mounted within a portion of the drive member, a driven memberhaving a cylindrical hub eccentric to the axis of the driven memberrotatively mounted in the coacting member parallel with and eccentric tothe axis of the drive member, clutch means interposed between the drivemember and the driven member adapted to be released by relative rotationbetween the drive member and the coacting member for transmittingdriving motion when there is no relative motion between the drivingmember and the cylindrical hub, and means for rotating the coactingmember relative to the drive member.

8. In a device of the class described, a sleeve having a slot extendingthrough the wall thereof, a shaft rotatively mounted within the sleeveand having a slot cut in its exterior surface, said slots havingdiiferent helical leads, a collar surrounding the sleeve, a pinprojecting from the collar through the slot in the sleeve and into theslot in the shaft, means for moving the collar axially on the sleeve, acylindrical hub carrying a crank pin and mounted for rotation in aportion of the shaft parallel with and eccentric to the axis of saidsleeve, clutch members mounted in the shaft and adapted to be releasedby relative rotation of the sleeve and shaft, said clutch membersadapted to transmit driving motion from the sleeve to the cylindricalhub, yielding means for holding the clutch members in driving contactwith the sleeve and the cylindrical hub, a connecting element betweenthe sleeve and the cylindrical hub for constraining the movement of thecrank pin relative to the sleeve axis, and means for limiting themovement of the crank pin.

9. An adjustable eccentric mechanism, comprising, -a drive member, acooperative member rotatably supported by the drive member, a rotatablecrank pin element mounted in the drive member, means for rotating thecooperative member relative to the drive member, a clutch between thedrive member and the crank pin element, and means for controlling themovement of the crank pin relative to the drive member axis when thecooperative member is rotated relative to the drive member.

10. The combination of a drive member, a cooperative member rotatab-lysupported relative to the drive member on the same axis and having acircular recess eccentric to the drive shaft axis,

a hub member in said recess, said hub member including a crank pin,means including angularly related slots in the drive and cooperativemembers respectively, a pin in the slots and a control lever moving saidpin for rotating the cooperative member relative to the drive member,and clutch elements between the drive member and the hub fortransmitting drive.

11. The combination of a drive member, a cooperative member rotativelymounted in the drive member on the same axis and having a circularrecess disposed eccentric to the drive shaft axis, a hub memberincluding a crank pin, means for rotating the cooperative memberrelative to the drive member, means including meshing gear teeth on thedrive member and the hub member respectively for controlling thedisplacement of the crank pin when the cooperative member is rotatedrelative to the drive member.

WALTER A. GARRATT.

